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  1. #1
    Join Date
    Nov 2004
    Posts
    446

    Absolute encoders?

    The galil card wont accept absolute encoder signals will it?

    It must have pulses to count?

    I just wanted to confirm my understanding that it wont accept. I am pretty sure I know why.

    thanks,

  2. #2
    Join Date
    Dec 2003
    Posts
    24221
    I know of no Galil card that will accept absolute encoders, typically absolute enc. are on average 12 bits wide, the usual advantage is that the position is known at power up, i.e. no requirement to zero the machine.
    Al
    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.

  3. #3
    Join Date
    Mar 2004
    Posts
    36
    If you go to Galils web site www.galilmc.com then under Tech Notes then under Feedback Devices you will find that they have setup Absolute Encoders in the past. The article describes a TR Absolute Encoder with standard differential line drivers A, A/, B, B/ ect..

    Al is correct it is best used to remember position if the power is lost or on machine startup.

    CamSoft also has a Save Position paramater that can plug the last encoder positions back into the position registers and readouts if you are using incremental encoders. I believe you would only use the the Save Position method if you do not have home switches.

    (group)

  4. #4
    Join Date
    Nov 2004
    Posts
    446
    Oh. that is way more information than I needed.. LOL

    That's what I like about this forum..
    Anyhow, I was just cementing my understanding of things..

    Thanks,

  5. #5
    Join Date
    Sep 2003
    Posts
    552
    Galil does offer a abolusute encoder interface. It is a daughter board to the main card, there are commands in the Galil manual I believe SI. I had bad noise problems with this encoder interface and the machine was finally switched to incremental encoders. Here is a pic.

    Darek
    Attached Thumbnails Attached Thumbnails 01.jpg  

  6. #6
    Join Date
    Nov 2004
    Posts
    446
    Quote Originally Posted by HillBilly
    Galil does offer a abolusute encoder interface. It is a daughter board to the main card, there are commands in the Galil manual I believe SI. I had bad noise problems with this encoder interface and the machine was finally switched to incremental encoders. Here is a pic.

    Darek

    Are those Grave Stones?

    Thanks for the info on the aux card.

    Murphy

  7. #7
    Join Date
    Sep 2003
    Posts
    552
    Architectural stone.
    Attached Thumbnails Attached Thumbnails 06.jpg  

  8. #8
    Join Date
    Nov 2004
    Posts
    446
    WOW!

    What size is that piece? How heavy?
    I'd like to see that baby in action...

    Murphy

  9. #9
    Join Date
    Dec 2003
    Posts
    24221
    I stand corrected, it looks like they also use a TR encoder by downloading a stored value first from the encoder and then revert to incremental.
    Al
    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.

  10. #10
    Join Date
    Nov 2004
    Posts
    446
    Quote Originally Posted by Al_The_Man
    I stand corrected, it looks like they also use a TR encoder by downloading a stored value first from the encoder and then revert to incremental.
    Al
    So does this mean that the galil board is interpreting the 8 bit or 12 bit (or whatever it is) signal as just one more encoder count??

    Thanks for the info AL

    Murphy

  11. #11
    Join Date
    Dec 2003
    Posts
    24221
    Evidentally there is two methods available for absolute detection with Galil, One is to use a TR encoder which when powered up send a pulse train of incremental pulses corresponding to the position and then reverts to regular incremental, the other is piggy-back hardware card which accepts binary absolute 12bit encoders.
    The Galil site explains both
    Al
    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.

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